small cabin light drained battery while on shore power?

[JonnyQuest]

Hi all,

Boats with battery systems are new to me, so this may be a complete newbie question. Last weekend we slept on our boat at the dock and it was hooked to shore power. We left a small interior incandescent cabin light on in the main cabin for the kids and it drained the house battery down to almost zilch.

Note: batteries are likely quite old.

I did expect that while hooked to shore power that the interior light would drain the battery, as the battery charger/conditioner (right term here?) would keep the battery topped off. Nothing else was on draining power.

Similarly: Throughout the week I was not on shore power and instead had a fold out solar panel hooked up to the charging system. When we arrived on Saturday the batteries were drained. I hooked up shore power and the batteries started charging again. Then later that night the interior light discharged the house battery as described earlier.

So is this normal? I expect not.
Suggestions?

Thanks for the ideas!

 

[nightowle]

is the water topped up in the battery? When you get a chance take the battery to an auto parts store that can run a check on it. It's probably old. I try not to run a light all night though - it's just like leaving the dome light on in your car. It'll run down the battery. And the small battery chargers can't keep up with that at only 1 or 2 amps per hour. Similar to small solar chargers and their capacity. Just my opinion.....not an electricity genius either!

 

[zeehag]

your charger is inadequate or there is a loss of connection somewhere --- run through the system thoroughly and check every little connection and the charger itself.. what brand isi t? how old is it? can water EVER get near it? (mine died due to drips into it) --try using a car charger to bypass it to see if that could be the problem and go for it!!!

the cabin light, if original fixture and kind of lamp, draws 3 amps per hour. if it is draining your battery , maybe you need new battery? how old are batts??? if more than 5 yrs, BUY NEW. then your problem is soilved--lol--but after checking everything, go buy trojan golf cart batts and wire them into 12 v banks and a cranker for the engine....DATE THEM so you know how old they are..LOL....have fun!!

 

[JonnyQuest]

Nightowle--good perspective about the car dome light, and I didn't realize that these chargers only handle 1-2 amps per hour or so. The charger is from a company that is may not be around any more-- BatCat brand, a yellow charger with a yellow charging indicator bulb and a green charged indicator bulb for each battery.

 

[JonnyQuest]

your charger is inadequate or there is a loss of connection somewhere --- run through the system thoroughly and check every little connection and the charger itself.. what brand isi t? how old is it? can water EVER get near it? (mine died due to drips into it) --try using a car charger to bypass it to see if that could be the problem and go for it!!!

the cabin light, if original fixture and kind of lamp, draws 3 amps per hour. if it is draining your battery , maybe you need new battery? how old are batts??? if more than 5 yrs, BUY NEW. then your problem is soilved--lol--but after checking everything, go buy trojan golf cart batts and wire them into 12 v banks and a cranker for the engine....DATE THEM so you know how old they are..LOL....have fun!!

A new boat for me, so not sure how old the charger is. It is a BatCat brand charger (boat is in mandeville right now), and I can find no real info on the charger or the company. Cabin lights are the original lights, so they are due to be swapped out.

When first arriving and finding the batteries drained I hooked up shore power and it was slowly charging-- could get a bit of a crank withint a couple of minutes. Bypassing and hooking up a car charger directly to the battery did charge teh battery quicker however, and was able to start up within 5 more minutes.

I need to figure out how to test teh electrical system components--have never done that stuff before. Any suggestions?

 

[Ross]

Jonny, If you are on shore power and have a recepticle on the boat plug in a nightlight from home for the kids. My boat is wired for shore power lights and recepticles and battery bank lights.

 

[Steve Dion]

How did you have the battery selector switch set? Not all boats are wired the same.

I prefer to have my battery charger completely seperate from the selector (1-2-ALL) switch. This way the batteries are always topped off when we are at the dock.

Obviously your batteries may be shot. If you take them somewhere that can test them you will find out quite quickly.

Be sure that you get your charger and the wiring checked out before you replace your batteries. There is no sense in destroying a couple hundred bucks in batteries by having improper wiring or charging.

 

[JonnyQuest]

How did you have the battery selector switch set? Not all boats are wired the same.

I prefer to have my battery charger completely seperate from the selector (1-2-ALL) switch. This way the batteries are always topped off when we are at the dock.

Obviously your batteries may be shot. If you take them somewhere that can test them you will find out quite quickly.

Be sure that you get your charger and the wiring checked out before you replace your batteries. There is no sense in destroying a couple hundred bucks in batteries by having improper wiring or charging.

Hi Steve and Ross.
Ross, I do have power receptacles so I'll bring an 110v lamp from home for the kiddos, great idea. Better fans too!

Steve, I hate to sound uninformed about my own boat system, but here's what I can say: it has a selector switch with the usual 1-2-all-off choice on it. Its a standard Blue Sea Systems switch. I can't say whether the charger is isolated form the selector switch like yours, but the PO told me to turn the switch to OFF while on shore power and the batteries will both be charged up. The bilge is obviously separate from the selector, and while my batteries appeared to be discharged, there was actually enough charge to manually activate the bilge pump by lifting the float. I'm guessing that the PO's instructions were accurate for setting the selector to OFF, and was merely to ensure that nothing would be drawing power while at dock.

Regarding the solar panel not charging the batteries and allowing them to discharge, I will have to look at the charger lights and the solar indicator light to see if the panel is even making a good connection to my system--perhaps there is corrosion on the contacts thwarting their ability to top off the batteries while at dock.

Good idea about having the charger and wiring checked out before replacing the batteries. Regarding batteries, if I ever am on the hook, my current two auto/marine battery system is not up to snuff for interior or exterior anchor lights. With a proper working system and two batteries, in general will there be enough capacity for running lights, anchor lights, and moderate interior light usage?

I thought I have read that a system with two properly working batteries (1 house, 1 starter) can supply general power needs for a night or two on hook-- is that an accurate understanding?

 

[nightowle]

try charging your batteries with the selector to 'both' instead of off. i thought the same thing about mine, but in order to charge both batteries in my house bank I need to leave it to 'both'.

 

[higgs]

You may need to upgrade your charger. A properly installed 3 stage charger won't care what your switch is set to and will easily keep up with your power demands. I run a frig, stereo, lights, fans, water pressure, etc on 12 V when plugged into to shore power with no drain on the house batteries. A good marine charger will cost around three bills, but they work great.

I would hesitate to buy a new battery until you solve this problem as nothing ruins a battery faster than repeatedly running it dead.

 

[JonnyQuest]

You may need to upgrade your charger. A properly installed 3 stage charger won't care what your switch is set to and will easily keep up with your power demands. I run a frig, stereo, lights, fans, water pressure, etc on 12 V when plugged into to shore power with no drain on the house batteries. A good marine charger will cost around three bills, but they work great.

I would hesitate to buy a new battery until you solve this problem as nothing ruins a battery faster than repeatedly running it dead.

Hey Higgs,
Do you have deep cycle batteries and how many? How much use can you get out of your system if you are overnight away from shore power? I like your ideas and need to educate myself on how to configure upgrades for my system.

Thanks!

 

[Clark]

Safe, reliable usage of a large Gp 31 battery (~110 Ah) is 50 Ah and that should take care of an anchor light for 12 hours, interior lights for the evening (~4-6 hr) and some radio/stereo usage. Now a good battery should provide more than that but you'll start eating into the total life cycles the battery starts with. Your second battery would be untouched and fresh, available for starting the engine. There are many ways to skin a cat but I would second the recommendation by others to get a decent 10-15 amp charger and read up on basic boat electrics.

FYI, we have a standard start battery for the engine and 2 Gp 24 deep cycle batteries in parallel for the house (160 Ah). Haven't had any load issues with this rig. I dare say, a good Gp 31 would probably carry us just fine but I'm thinking of adding a small DC-AC inverter for occasional use away from the dock so I rigged the 2 Gp 24's in anticipation of that.

 

[Clark]

A followup . . . if you use (and continue to use) a pair of 'normal' Gp 27 wet cell batteries, the Xantrex Truecharge 10TB has been around for quite a while and has a good reputation. They have a 10 amp capacity and can charge 2 batteries and are ~ $150 from Defender. They are hardwired so that may be a consideration.

 

[JonnyQuest]

Suggestions for charging and electrical monitoring system brands?

First off, thanks to everyone for all the input.

A couple of specific questions:

1. When on shore power, do certain charger systems selectively route power to energize the appliances being utilized, or do all chargers simply feed the batteries and the appliances draw off of the batteries? It seemed like the ProMarine ProTech1240i Plus literature suggests that it will differentially send enough power directly to the house system so that your appliances aren't discharging your batteries while on shore power. Do I understand that correctly?

2. Is hooking an electrical monitoring system important? I read comments on Cruisers Forum that those with them love them; I guess its nice that they provide % charge remaining, among other things. Thoughts on electrical system monitors?

Thanks again for the input here.

 

[Stu Jackson]

If you don't want to buy a book and keep depending on the internet for answers, you're gonna a find a lot of varied opinions.

You might start reading the West Marine Advisor columns, very highly recommended. It'll at least help you over the newbie hump so you can start making decisions and asking questions that are more than just the basics. Scroll to Electrical and read them all.

http://www.westmarine.com/webapp/wc...51&catalogId=10001&page=West-Advisor-Articles

For instance, when you ask how long you can stay out overnight, you have to be comparing apples & apples. Some folks with boats your size have fridges, which use up 60 ah per day. You need to do an energy budget to figure out what size battery bank you need.

 

[JonnyQuest]

Thanks for the link Stu.

I just picked up one book from the local West Marine store, and have a couple more on order. A video on maintenance issues too.

My learning curve is a bit drawn out since the boat is docked a couple of hours away from home for now (oil spill preventing me from sailing it back home). The books should get me more up to speed though.

Thanks again for the ideas.

Cheers!

 

[Clark]

Like Stu says . . develop an energy budget and get a decent estimate of everything that you'd use. Select your battery accordingly - use the 50% discharge guideline for capacity. If what you have is too old or too small get good quality deep cycle batteries then select your charger.

Answers:
1) Yes, most chargers designed for dockside continuous use will provide the current needed for DC devices while on shore power. A 40A charger is pretty big depending on what batteries you have and what usage you'll see (see above - other owners with larger banks use 40 and 60 amp chargers)
2) Monitors are important if you have a large bank and cruise for days at a time. They give you good info as to how much energy goes into a battery and how much you take out. Voltmeters by themselves won't do that. If you are a day sailor or typically only spend 1 or 2 nights away from a dock, they may be a bit overkill.
Hope this helps.

 

[JonnyQuest]

Clark, that did help, giving me a sort of perspective to continue on with from here. Next time I get to the boat I'll do the energy calculations and go from there.

Have a great day.

 

[higgs]

Johnnyquest

I am no expert and am still figuring out how to manage my batteries at anchor.

I have two type 27s, but if I leave the frig on with an anchor light and no shore power they go dead overnight. I used to start with #1 and as it lost power went to #2. I am now using both house batteries at the same time. At anchor ( I have a separate starter battery) I have not yet been able to determine how that works. My thinking is that it is a lot better to run two batteries half way down than each one all the way. One thing I am going to try is turning off the frig overnight figuring it will stay cool enough if not opened. I also bought a solar powered garden light that I am going to use as an anchor light. Have not put this all into play yet.

 

[dparilla]

If you would like, I can send you some schematics on how we set up our system. We have an O'day 35, and I have a pretty robust AC and DC distribution covering several "outlets" along with stereo, gps, VHF, a 1000 watt inverter, loran and even an AC/DC refrigerator. I currently have a guest 20 amp charger to maintain the house and starter batteries (though I am going to upgrade that this next off season,) and have installed an automatic charge relay (ACR) and a new master panel that elimantes having to remember which bank ran last etc. I tried to make it as simple as possible to operate, and maintain. This is our third season with this setup and it has served us well for both short weekender trips as well as a few coastal cruises. I don't have a battery monitor system, just a voltmeter and ammeter. Let me know if you want more info. I can also recommend Nigel Calder's Book, The Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems. Found it on amazon (as linked above.)
Fair Winds for now,
Dan